This invention relates to an automatic linearity correction circuit designed to improve the linearity of outputs of junction transistors by use of the properties of dual-gate MOSFET.
Junction-type active elements such as a junction transistor, junction field-effect transistor, junction diode, etc. are generally used for amplification, modulation and demodulation of weak signals. FIGS. 1A and 1B show examples of static characteristic curves of a junction transistor and of a junction field-effect transistor. These curves apply to amplification, modulation and demodulation of said weak signals.
When these static characteristic curves as shown in FIGS. 1A and 1B are obeyed, however, it is difficult to completely maintain linearity between input and output, resulting in bad linearity, because an output signal taken from a point near a strongly rising region of collector current IC or drain current 1D is not proportional to the input signal.